2. Basic summary of a Gear Box:
Gear mechanisms are used to mechanically alter the output of power
or velocity in a system. This is useful when particularly heavy items cannot
be lifted with an initial supplied amount of force and so gears can be used.
Aim:
Our primary goals are to lift a mass of 8kg successfully. Once we have a design
that achieves this we will aim to improve the design by lifting the mass quickly,
lifting a larger mass, minimizing the largest axial length etc…
Group Meeting
◦ Discuss details, aims and methods for the project.
◦ Determine simple designs and concepts.
◦ Understand marking criteria
◦ Distributing tasks between team members
3.
4. Calculations:
1. Find Torque of the motor
2. Find the Torque needed to lift the weight
3. Find the arrangement of gears that best suits our goals
4. Find the angular velocity of the motor
5. Find the angular velocity and tangential velocity at the
6. Time taken to lift the 8kg mass one meter
5. Pros Cons
Traditional spur: High torque/gear ratios
Simple design
Lower accuracy and
torsional rigidity due to
straight cut gears.
Low Speed.
Prone to wear
Planetary: Higher precision.
Compact
High torque/gear ratio
High bearing loads
Less tolerance for
interference
Complex design
Bevel: Can be more compact Not practical from the
chosen material
Helical: Provide more power
Less noise
Not practical for chosen
material
Choice of Gear type:
Choice of Gear type conclusion:
Spur gears have been chosen.
7. Variables:
◦ Calculations don’t take into account that the string wrapping around
the shaft will slightly increase velocity and increase the torque needed.
◦ There will have to be considerations in regards to the minimum
tolerances capable of the CNC laser cutter.
